The invention relates to the field of pyrotechnic initiators that are ignited or primed by means of a light energy signal. This type of initiator is referred to as an opto-pyrotechnic initiator. The invention relates particularly, but not exclusively, to applications in space launchers where opto-pyrotechnic initiators are used for performing numerous pyrotechnic functions.
In known manner, an opto-pyrotechnic initiator comprises a pyrotechnic charge arranged in a cavity, an optical fiber connected at a first end to a source of light radiation, e.g. a laser diode, with the other end of the optical fiber being placed in the proximity of the pyrotechnic charge in order to transmit the light radiation thereto and ignite it.
The connection between the optical fiber and the body of the initiator is generally made by sticking the fiber in a ferrule with a gasket or directly to the body. That type of connection presents several drawbacks, in particular when the initiator is to be exposed to high temperatures and pressures. In particular, a connection between an optical fiber and an initiator body made by means of an adhesive possesses a lifetime that is limited because of organic substances that are present in the connection degassing so that the connection degrades over time. In addition, the mechanical and/or thermal strength of that type of connection is not guaranteed under temperature conditions of several hundreds of degrees Celsius and pressures of several hundreds of megapascals. Furthermore, that type of connection is complex and onerous to implement, in particular because of the need to use several different elements (ferrule, gaskets) in order to make the connection.
There thus exists a need for an opto-pyrotechnic initiator that is suitable for withstanding severe temperature and pressure conditions and for operating in those conditions, and to do so with lifetimes that are long, while also being suitable for being fabricated industrially.